When IC components, precision machinery components, etc. are produced, cleaning the components with organic solvent is usuarlly performed heretofore to remove flux, dust, etc. adhered to the components in a process of assembly.
1,1,2-Trichloro-1,2,2-trifluoroethane (hereinafter referred to as R-113) is widely employed as the organic solvent. R-113 is nonflammable, low in toxicity in vivo and excellent in stability. In addition, R-113 has a moderate solubility so that R-113 selectively solubilizes a variety of dirt without attack on metals, plastics, elastomer, etc. When flux on printed-circuit board is cleaned, R-113 is particularly advantageous, because the cleaned articles are composite components made of metals, plastics, elastomer, etc., in most cases.
Since R-113 is suspected of destructing the ozonesphere, as a result, causing cutaneous cancer, utilization of R-113 is gradually controlled.
Cyclic fluorinated hydrocarbons such as 1,1,2,2,3,3-hexafluorocyclopentane disclosed in U.S. Pat. No. 5,176,757 and 1,1,2,2-tetrafluorocyclobutane disclosed in Japanese Unexamined Patent Publication No. 5-140594 are known in addition to R-113 as cleaning solvents.
Since the known cyclic compounds have a number of hydrogen atoms leading to flammability, the compounds may cause a trouble on safety as a cleaning agent when used at elevated temperature and recycled.